A turbine is a machine that includes a moving component, commonly referred to in the art as a rotor, or spin mechanism, which is mechanically driven using the energy from a fluid flow, such as wind, steam or water. The spin mechanism typically includes a main shaft, or drum, from which a plurality of blades project. In use, the moving fluid is drawn into contact against the blades so as to impart rotational energy onto the rotor. The turbine then converts the rotational energy into other forms of energy, such as electrical energy, to optimize its usefulness.
A wind turbine is one form of turbine that utilizes naturally occurring wind energy to produce electrical energy. One type of wind turbine that is well known in the art includes a rotor with a plurality of enlarged propeller-like blades, or fins, that project radially outward from a common shaft in an equidistantly spaced arrangement. Depending on the orientation of the common shaft, the plurality of blades is adapted to rotate along a vertical or horizontal plane. Typically, the blades of the rotor are mounted at a significant elevation (e.g., on the top of an enlarged steel tube tower or other similar structural support) to maximize direct exposure to wind forces.
By coupling the rotor shaft to an electromechanical device, such as a generator, the rotational energy generated from the fluid flow forces can be converted into electrical energy. In this manner, wind turbines are able to produce electricity from fluid flow forces that are naturally occurring. Accordingly, it is to be understood that the naturally occurring fluid flow forces serve as a non-consumable, carbon-free fuel for producing environmentally-friendly, or clean, electricity, which is highly desirable.
As referenced briefly above, the spin mechanism for conventional wind turbines typically relies on an open blade construction (i.e., with the blades uncovered and externally exposed). As can be appreciated, the open blade construction used in traditional wind turbines has been found to introduce a number of notable drawbacks.
As a first drawback, the open blade construction used in traditional wind turbines has been found to create an environmental danger to wildlife. Most notably, birds that fly within the immediate environment of the turbine are susceptible of being struck by the rotating blades. To promote greater wildlife safety, turbine blade speed is often significantly reduced. However, a significant reduction in rotor speed is typically achieved by substantially increasing the overall size of the turbine blades. As can be appreciated, a sizable increase in turbine blade size often creates significant zoning and aesthetics issues.
As a second drawback, the open blade construction used in traditional wind turbines has been found to be relatively inefficient. Among other things, traditional wind turbines provide no means to harness, or otherwise control, the wind flow used to drive the rotor, thereby rendering their manufacture and operation rather expensive in nature.
As a third drawback, the open blade construction used in traditional wind turbines has been found to produce a significant amount of noise during normal operation, which is highly undesirable.